Arkaine's Valor is one of the few Diablo I unique items that were also found in Diablo II. Still, it was not available before Diablo II: Lord of Destruction.

As seen above, it is a Ring Mail in Diablo I but an eliteSplint Mail in Diablo II. It is assumed that it was retconned because of its Diablo I image shows an armor similar to Japanese o-yoroi, a type unrepresented in the artworks available to Diablo II unique items.